Re: [PATCH v2] x86/CPUID: unconditionally set XEN_HVM_CPUID_IOMMU_MAPPINGS

[Jan Beulich <jbeulich@xxxxxxxx>]

On 19.01.2021 15:31, Roger Pau Monné wrote:
> On Tue, Jan 19, 2021 at 03:26:22PM +0100, Jan Beulich wrote:
>> On 19.01.2021 14:07, Roger Pau Monne wrote:
>>> This is a revert of f5cfa0985673 plus a rework of the comment that
>>> accompanies the setting of the flag so we don't forget why it needs to
>>> be unconditionally set: it's indicating whether the version of Xen has
>>> the original issue fixed and IOMMU entries are created for
>>> grant/foreign maps.
>>>
>>> If the flag is only exposed when the IOMMU is enabled the guest could
>>> resort to use bounce buffers when running backends as it would assume
>>> the underlying Xen version still has the bug present and thus
>>> grant/foreign maps cannot be used with devices.
>>>
>>> Signed-off-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>
>>
>> Acked-by: Jan Beulich <jbeulich@xxxxxxxx>
>>
>> This time for real, I suppose.
> 
> Won't believe it until it hits the repo ;).

There you go. But well, we can always revert ... ;-)

Jan